How to make a portable handy lie detector in Altoid tin

Hi. I'm paewookyung, and this is my first posting in this site. please take note that
english is not my mother tongue. so please understand some of my gramatic mistake.;

Anyway, let's get this started!
This is a portable lie-detector built in Altiod tin. maybe you could have some fun useing this thing.

note: this detector is less sensitive then a real one. this could be miss some (many) of the lies.

Step 1 Things you'll need.

You will need some things below for this project.

1. circuit board
2. 10K& resister
3. 47K& resister
4. 470& resister
5. 1M& resister x2
6. 47K& VR
7. knob for VR
8. 2N3904 transistor x3
9. 0.1 ? mylar cap
10. slide switch.
11. 9V bettery snap
12. LED (one red, one green)
13. solding tools.
14. drill
15. basic tools,
16. valcro
17. aluminum foil
....and most of all, Altoid tin!

Comments

[Socco]

err, your LEDs are incorrect on the schematic and should be swapped so that the L1/Green is on the left and L2/Red is on the right. Then, when the probes are squeezed (or put on tongue) to reduce their impedance the Red LED will light, as expected. I found this after building the circuit.

[robot1398]

what do you mean by 0.1 mylar cap and 1M& resister x2

[static]

In Stating the obvious a potentiometer IS a variable resistor, but identifying it as potentiometer is best. Because search for a variable resistor will bring an overwhelming items for beginners to consider. Beginners will be faced with choice between an audio/logarithmic taper (volume control) or a linear taper. No doubt for this project they would want a linear taper, although an audio taper would function.

[lespaul55]

WHAT IS THAT BLUE CYLINDER SHAPED THING? The skematic says its the VR but the vr is attached to that thing. I though it mught be the mylar cap but thats the red one. Please Help!!!

[lespaul55]

Its an extra cap that you don't need.

[robot1398]

hi

[noliver]

47K& VR another 47k and whats a VR? cause i googled it and it came a 1,000,000 bucks and yes im an electrical navis plz reply soon

[paewookyung]

It means 'Variable resistor' or 'Volume resistor'.
Just get to your local electronic store and ask for it.
it'll probably available in most part of the world....

[Sohaib Asif]

is this real lie detector??????????????

[D1g1talAli3n]

Will a 50K VR work?

[D1g1talAli3n]

Will a 50K VR work at all?

[porcupine_malik99]

you are using two capacitor but in diagram there is only 1 capacitor? whre would da 2 one placed?

[Jimmy Proton]

He said in an earlier picture that the electrolytic capacitor is optional, if that helps.

[lespaul55]

What's the uF of the electrolytic capacitor?

[LiLGq]

um.....people.....can i ask a question about the 47VR he wrote there if it is a potentiometer so how much is the value?????....and another thing is what is a mylar cap????.....and how much is the correct value of it 'cause there are 2 caps there....the .1 and the 100..so which is the cap really used to this project???....

[mwagner63]

In the schematic it says 100nf

[LiLGq]

tnx....

[mwagner63]

Also I couldn't find the 100nf capacitor so I looked around and it is actually .1uf

[lespaul55]

Yes there are!!! ^^^

[isamuel]

what is this thing detecting?

[lespaul55]

I'm pretty sure the electrical pulse in you fingers. Generally speaking it increases when someone is lieing. I haven't made this design so I don't know the sensitivity of the readers.

[lespaul55]

What does VR stand for? Where do I get one?

[lespaul55]

Variable Resistor

[lespaul55]

What A is the switch and what is the round blue thing in the first picture?

[SUBYRIDA25]

Hi, Could you show the back of the circuit. I'm new to the electronics game and could use a little help. Thanks

[Telecom_Student]

You Should Of Cut Your Wires Shorter It Would Look Neater.

[MROHM]

Yes You're Right,,The Neater and more direct the wiring the Better the chances you have to get this little baby to work the First Time!! I like the Design of your Circuit,,Awesome!!

[kengelman]

can anyone show me what the back of the finished circuit board looks like?

[frollard]

a bunch of wires soldered between the components.

[Boowiggins]

Hey People - even the ones pros use exhibit the same discrepancies. Use this detector in combination with facial expression, and other "tells" that the subject might exhibit to determine the validity of their statements.

The best tool in the hands of a fool is worthless. The worst tool in the hands of a genius is exemplary!

[Boowiggins]

I SO want to make one of these! Thanks. I'm going to extend the LEDs and position holes in the lid, so that when closed I can still tell if the Joker is lying! And now, "To the Batcave!"

[robert0joe]

Can I use AA batteries instead of 9V? Like 2 AAs?

[LiLGq]

well obviuosly its not bearable because 9v batt has 9 volts while 2AA battz has only 3 volts...

[static]

Here the voltage needs to be high enough to insure there is a small current flow over the skin of the suspect. Probably best to stay with 9V, unless you are willing to work with different resistor values to find if this would function at a lower voltage.

[hintss]

6 in series, I think

[mederick]

no..............but you can get some at pep boys in packs of 20!!!!!!!!!!!!

[doudibeik]

do you wrap the foil all the way around the velcro or do you glue in on the edge?

[vaxiong39]

Where can I buy most of these stuff

[Jimmy Proton]

eBay!

[zack247]

radio shack. or if you live in canada, "the source". i dunno about anywhere else in the world, though. everything should be in the store though